Various temperature measuring sensors intended for use in the medical and other fields are known. Efforts have been made to manufacture such sensors, as well as the instruments on which they are utilized, as cheaply and simply as possible, primarily in order to make these devices disposable after use. It is thus intended that such devices be made which can be thrown away, and which need not be reused.
On the other hand, it nevertheless remains essential, particularly since these devices are intended for use in the medical field, that these devices be capable of use with a degree of accuracy such that reliance can be placed on the values read from them. This is of particular importance during medical examinations, for example. Besides use in the medical field, however, those having knowledge of this business will also understand that such a device can be used in other fields, such as in connection with purely industrial applications where a simple and cheap, but nevertheless reliable temperature reading is required.
Several different designs of thermometers including such temperature measuring sensors, and in which the temperature sensors of the present invention could be incorporated, are set forth in the prior art. These include U.S. Pat. Nos. 4,317,367; 4,296,663; and 4,253,334; and U.S. Pat. No. 4,382,246. Furthermore, U.S. Pat. Nos. 4,200,970 and 4,236,298 disclose processes for adjusting thermistors which are to be fitted as temperature sensors in other thermometer designs therefor. However, these and other known processes for adjusting thermistors and the like suffer from the disadvantage that heat is developed in any mechanical processing utilized in order to adjust the electrical property, such as resistance, of the temperature sensitive portions of these sensors. Thus, it becomes quite difficult to measure these properties as a control at a precisely predetermined temperature.
Furthermore, U.S. Pat. No. 4,041,440 discloses thermistor-resistor networks produced from thick films, and methods of adjusting the overall resistances of same. Thus, in FIGS. 1 through 4 thereof this patent includes various configurations of separated thermistor and resistor thick film portions, interconnected by conductive portions, and specified means for adjusting specific sections of these conductive portions so as to alter the resistance of the thermistor component, as well as means for altering the resistance of the resistive component thereof.
However, none of this art has disclosed methods for adjusting the resistance of such sensors which can be carried out in a simple and accurate manner so as to produce a disposable thermometer including these temperature sensing elements therein.